Very Odd Question About Sailfin Molly

[LaurenRhiain]

I've had my Black Sailfin Molly since 24th Dec 2012 now and it shows some rather odd behaviour. Basically it chases my platies around for ages trying to eat their poo. It's not nipping at them or showing any aggression, it just seems to be after their waste. Is this normal as I've not seen any other fish do this before? 

 

[Chad]

It is normal. Many fish eat the waste of other fish. In my reef tank when the large yellow tang poos it's a feast.
The behavior can be stopped or reduced with a change in diet. For example when I notice my fish eating the tang's poo I add more algae to feeding times and that seems to work.